Effects of catalpa alcohol from Rehmannia glutinosa on calcium-binding protein, interleukin-1β and galectin-3 in synovial tissues of rats with knee osteoarthritis

We aimed to evaluate the effects of catalpa alcohol from Rehmannia glutinosa on the expressions of calcium-binding protein (S100A12), interleukin-1β (IL-1β) and galectin-3 in the synovium of rats with early knee osteoarthritis (KOA). Fifty-two adult male Wistar rats aged 3-8 weeks were divided into normal control (n=16), model (n=12), low-dose (n=12) and high-dose groups (n=12). On the 10th day after modeling, 6 rats in normal control group and 6 in other three groups were randomly selected. X-ray and three-dimensional CT images of left knee joint were taken under live anesthesia. The joint cavity of sacrificed rats was opened to observe cartilage surface. After 28 consecutive days of administration, the synovial tissue of left knee joint was collected. S100A12, IL-1β and galectin-3 levels in synovial tissue were detected by immunohistochemistry and ELISA. There were articular cartilage defects in left knees. Radiological examination showed significant joint space narrowing and hyperplasia, and 3D CT joint space value decreased (P < 0.05). The Mankins and OARSI scores of synovial histopathology were significantly different (P < 0.05). The S100A12, IL-1β and galectin-3 levels in synovial tissue of model group significantly exceeded those of normal control group (P < 0.01). Compared with model group, such levels of low-dose (P < 0.05) and high-dose groups (P < 0.01) were significantly lower. The S100A12, IL-1β and galectin-3 levels in synovium tissue decreased with rising concentration of catalpa alcohol from R. glutinosa . Therefore, this drug is potentially suitable for inhibiting inflammatory response to delay the progression of KOA.